Based on the willingness to make good use of energy power, a wind power generating device to be mounted on a transportation vehicle, such as a scooter or a car, has been developed such that, when the transportation vehicle is running, the generated wind power accompanying the wind flow can be converted into kinetic energy and then further be converted into electric energy.
The structure of this kind of wind power generating device mainly includes a blade, a drive shaft and a power generator, the blade being able to be driven by wind power to rotate thereby converting kinetic power of the wind into mechanical energy of the drive shaft so as to drive the power generator to rotate to generate power.
However, when the running speed of the transportation vehicle becomes so fast that the wind flow speed become too fast, the blade and the power generator can burn up and break because of a too high speed rotating. Therefore, an improvement for the wind power generating device of transportation vehicle is needed.